Iranian Scientific Fisheries Journal

fa مقاله علمی – پژوهشی:‌ اثر خوراکی سطوح مختلف کیتوزان بر عملکرد رشد، ترکیب لاشه و شاخص‌‌های ایمنی- بیوشیمیایی سرم خون فیل ‌ماهی (Huso huso) انگشت‌قد Dietary effect of different levels of chitosan on growth performance, carcass composition, and blood immune-biochemical indices of Beluga (Huso huso) fingerlings تغذيه تغذيه پژوهشي Research تحقیق حاضر به منظور بررسی اثرات سطوح مختلف کیتوزان به عنوان یک مکمل غذایی محرک رشد و ایمنی بر عملکرد رشد، ترکیب لاشه و برخی شاخص‌‌های ‌‌خونی و سرم‌‌ شناسی بچه فیل&rlm;ماهی پرورشی (Huso huso) طراحی و اجرا گردید. تعداد 1260 عدد &rlm;بچه فیل &rlm;ماهی (07/0±87/2 گرم) در 18 مخزن فایبر گلاس 2000 لیتری (70 عدد ماهی در هر مخزن) با شش جیره آزمایشی شامل جیره شاهد (فاقد کیتوزان، T1)، کیتوزان با مقادیر 15/0 درصد (T2)، 3/0 درصد (T3)، 45/0 درصد (T4)، 6/0 درصد (T5) و 75/0 درصد (T6) با 3 تکرار در هر تیمار به ‌‌مدت 12 هفته تغذیه شدند. وزن نهایی، شاخص رشد ویژه، نسبت بازده پروتئین و ضریب تبدیل غذایی ماهیان تغذیه شده با سطوح 45/0 درصد و بالاتر کیتوزان به طور معنی‌داری نسبت به نمونه شاهد کمتر بود (05/0p<). میزان پروتئین و چربی لاشه با افزایش میزان کیتوزان در جیره غذایی نسبت به گروه شاهد به‌ترتیب افزایش و کاهش معنی‌داری داشت (P≤0.05). شاخص&rlm;های ایمنی لیزوزیم، کمپلمان ACH50، ایمونوگلوبولین تام و IgM نیز با افزایش میزان کیتوزان در جیره غذایی نسبت به گروه شاهد افزایش معنی‌‌داری یافت (05/0p<). در نتیجه، به منظور دستیابی به حداکثر رشد، ترکیب بهینه لاشه و شاخص‌‌های ایمنی- بیوشیمیایی خون در بچه فیل ماهی پرورشی، پیشنهاد می&rlm;شود از میزان 6/0-45/0 درصد کیتوزان در جیره غذایی این ماهی استفاده گردد. Introduction Aquaculture is increasingly vital for meeting the protein needs of a growing global population. Successful production relies on efficient feed, which accounts for 60% of costs, and the development of high-quality products. Disease management in aquaculture is challenging due to factors like poor nutrition and environmental conditions, making prevention more critical than treatment (Ndashe et al., 2023). Current strategies focus on using immune stimulants and additives, such as organic acids, probiotics, and prebiotics, to enhance fish health and resilience against diseases (Dawood et al., 2018). The use of natural growth stimulants like chitin, chitosan, and lactoferrin has surged due to their economic benefits and minimal environmental impact. These substances not only improve immune responses but also enhance the antibacterial activity of phagocytic cells, contributing to sustainable aquaculture practices. Overall, the shift towards these natural alternatives reflects a growing recognition of their value in promoting fish health and reducing reliance on chemical treatments. Chitosan is a biodegradable and biocompatible polysaccharide derived from glucosamine through the deacetylation of chitin, predominantly found in the exoskeletons of crustaceans, particularly shrimp shells. It offers numerous benefits in aquaculture, notably enhancing fish health and growth. Chitosan stimulates the immune system by increasing levels of immunoglobulin M (IgM) and lysozyme activity, which improves disease resistance. It also boosts antioxidant capacity by enhancing the activity of enzymes like superoxide dismutase (SOD) and catalase (CAT), thereby reducing oxidative stress. Additionally, chitosan promotes gut health by increasing intestinal villi length and digestive enzyme activity, facilitating better nutrient absorption (Mukarram et al., 2023; Zhang et al., 2024). Moreover, chitosan can chelate heavy metals such as cadmium, mitigating their toxic effects on fish, and its antibacterial properties help maintain gut microbiota balance by preventing pathogenic bacteria while promoting beneficial ones. Overall, dietary chitosan supplementation has been shown to enhance growth, health, and stress resistance in various fish species, making it a valuable additive in aquaculture. In the context of sturgeon (Huso huso) farming in Iran, reducing juvenile fish mortality and increasing growth rates are critical for economic efficiency, highlighting the importance of suitable diets and micronutrient balance to enhance immune function and production efficiency. Methodology The extraction of chitosan from shrimp shells was carried out through four stages: demineralization, deproteinization, decolorization, and deacetylation. 1260 fish (2.87 ± 0.07 g) after passing the acclimatization period, were fed in 18 tanks with six experimental diets, including control diet (without chitosan, T1), 0.15% (T2), 0.3% (T3), 0.45% (T4), 0.6% (T5) and 0.75% (T6) of chitosan (n=3) for 12 weeks. Then all growth indices such as final weight, growth rate, Protein Efficiency Ratio, and FCR, immunological parameters like lysozyme, ACH50, total immunoglobulin, and IgM were measured. The body composition also was measured after 12 weeks. Results The final body weight and body weight gain in treatments containing 0.45%, 0.6%, and 0.75% chitosan were significantly higher compared to the control, 0.15% and 0.3% chitosan treatments. The specific growth rate significantly increased with the higher levels of chitosan, and no significant difference was observed in the group fed with 0.15% chitosan compared to the control group. The hepatosomatic index significantly improved in all chitosan-fed treatments compared to the control group (P≤0.05). The feed conversion ratio significantly improved with increasing levels of chitosan compared to the control group. The protein efficiency ratio also increased in the treatments fed with 0.45%, 0.6%, and 0.75% chitosan compared to the control group, but no significant differences were found in the treatments fed with concentrations of 0.15% and 0.3% chitosan (P≥0.05). The lowest carcass protein level was observed in the control treatment, which showed a statistically significant difference compared to the carcass protein levels of other treatments, except for the 0.15% chitosan treatment (P ≤ 0.05). The carcass protein levels in the 0.45%, 0.6%, and 0.75% chitosan treatments were the highest, but no significant differences were observed among them. The carcass fat level in the 0.45%, 0.6%, and 0.75% chitosan treatments was significantly lower compared to the control group (P≤0.05). With the increase in chitosan concentration in the diets, the serum lysozyme levels significantly increased except for the group consuming 0.15% chitosan (P≤0.05). The results obtained from the complement activity (ACH50) measurements showed that with the increase in chitosan levels in the diet, this indicator significantly increased in the serum (P≤0.05). The total serum immunoglobulin and IgM levels, also increased significantly compared to the control group (P≤0.05). Discussion and conclusion Chitosan, has gained attention in aquaculture for its potential as a growth promoter and immunostimulant. Research indicates that dietary chitosan enhances growth performance, feed efficiency, and immune responses in various fish species, including Nile tilapia, common carp, and golden pompano. Optimal chitosan levels, typically ranging from 0.5% to 2%, have been shown to improve weight gain, feed conversion ratios, and overall health status by promoting gut health and enhancing digestive enzyme activities. Studies also highlight chitosan's role in modulating serum biochemical parameters, reducing fat accumulation in the liver, and improving intestinal morphology. The balance of chitosan dosage is crucial, as it can enhance beneficial bacteria while inhibiting harmful ones, thereby supporting the fish's immune system. Overall, chitosan represents a promising, eco-friendly alternative to antibiotics in aquaculture, contributing to sustainable fish farming practices while improving the health and productivity of cultured species. Chitosan also enhances nonspecific immunity and reduces mortality in fish, as evidenced by studies on common carp (Maqsood et al., 2010). However, its effects on feed consumption and conversion ratios can vary, with some studies showing no significant impact on these parameters despite improvements in liver health (Stanek et al., 2023). Overall, chitosan's role in aquaculture highlights its potential as a dietary supplement to improve fish health, growth, and resistance to environmental stressors. Serum parameter measurements are crucial for assessing the metabolic and physiological health of fish, particularly in aquaculture where they are susceptible to opportunistic bacterial infections. Lysozyme activity, an indicator of immune health, was found to increase with dietary chitosan levels. Research indicates that chitosan enhances lysozyme activity across various fish species, including loach, cobia, silver carp, vannamei shrimp, and rainbow trout. Additionally, chitosan supplementation in diets for beluga sturgeon and hybrid sturgeon also boosted lysozyme levels. Chitosan's immune-boosting effects are attributed to its ability to scavenge free radicals, enhancing innate immunity. Complement activity, vital for non-specific immune responses, also increased in fish like Nile tilapia and mrigal when fed chitosan. However, responses to chitosan vary by species and concentration, with some studies indicating potential negative effects at higher doses. Furthermore, IgM levels, a key immunoglobulin in fish, significantly increased with chitosan supplementation, reinforcing its role in adaptive immunity. Overall, optimal chitosan levels in fish diets can significantly enhance immune responses and health. The increase in IgM levels with dietary chitosan is not fully understood, necessitating further research to clarify the mechanisms involved (Salam et al., 2024). Studies indicate that chitosan enhances IgM and total protein levels in fish, such as rainbow trout and golden pompano, although excessive chitosan (10 g/kg) can reduce these benefits (Yu et al., 2023). In tilapia, IgM levels increased significantly up to 1.5% chitosan but decreased at 2% (Zhang et al., 2024). Additionally, recombinant chitosan nanoparticles show promise as alternatives to antibiotics in aquaculture, potentially enhancing disease resistance. This research supports using chitosan in beluga fry diets to improve growth and immune performance while reducing antibiotic reliance, particularly at levels of 0.45% to 0.6%, which positively affected growth, body composition, and immune parameters. Conflict of Interest The authors declare that they have no conflict of interest. Acknowledgment The authors wish to convey their heartfelt appreciation to all colleagues who supported and facilitated the experiment's necessary infrastructure. فیل‌ماهی, کیتوزان, رشد, ترکیب لاشه, شاخص‌‌های ‌خونی Chitosan, growth rate, carcass composition, blood parameter, beluga 49 65 http://isfj.ir/browse.php?a_code=A-10-579-19&slc_lang=fa&sid=1 Mahmoud Mohseni محمود محسنی mahmoudmohseni73@gmail.com 100319475328460039495 100319475328460039495 Yes 1- International Sturgeon Research Institute انستیتو تحقیقات بین المللی ماهیان خاویاری Fatemeh Fadakar Masouleh فاطمه فداکارماسوله Fadakarfatemeh62@gmail.com 100319475328460039496 100319475328460039496 No 1- International Sturgeon Research Institute انستیتو تحقیقات بین المللی ماهیان خاویاری Mostafa Karami Nasab مصطفی کرمی نسب Karaminasab@aol.com 100319475328460039497 100319475328460039497 No 2- Behdaneh Shomal Animal, Poultry and Aquatic Feed Production Cooperative 2- شرکت تولید خوراک آبزیان بهدانه شمال Donya Zakeri دنیا ذاکری donyazakeri1@gmail.com 100319475328460039498 100319475328460039498 No Shahid Beheshti University دانشگاه شهید بهشتی